Photosynthesis — both anoxygenic and oxygenic — allows access to new sources of energy. Oxygenic photosynthesis has the potential to create an oxygen-rich atmosphere and so allow aerobic respiration, which yields much higher amounts of energy than anaerobic respiration. The amount of oxygen added to the atmosphere is intimately linked to the burial of organic matter in sediments, therefore marine phytoplankton are crucially important in maintaining the levels of atmospheric oxygen on Earth. Anoxygenic photosynthesis will have a positive Gaian effect by providing an important source of energy. Oxygenic photosynthesis is more problematical; as with anoxygenic photosynthesis it provides an energy source, but the oxygen given off is likely to be toxic to organisms evolved in anoxic conditions. It is currently impossible to know if we should expect most biospheres to evolve oxygenic photosynthesis. However, improvements in telescope technology should allow us to look for oxygen-rich atmospheres around distant Earth-like planets.
Oxford Scholarship Online requires a subscription or purchase to access the full text of books within the service. Public users can however freely search the site and view the abstracts and keywords for each book and chapter.
If you think you should have access to this title, please contact your librarian.